Ask HN: Is there anyone here who still uses slide rules?

Current usage and niche applications

• Some pilots regularly use E6B “flight computers” or circular slide rules for planning and as power‑free backups, even if actual flying is done with ForeFlight or glass cockpits.
• Others use slide rules or circular variants on watches for quick ratios, unit conversions, travel time estimates, or even cricket run rate.
• A few people designed or 3D‑printed custom slide rules for games (e.g., Balatro) or graphics scaling, or keep one in an “apocalypse kit.”
• Several mention using them occasionally for back‑of‑the‑envelope estimation, especially when inputs are approximate anyway.

Nostalgia, heirlooms, and collecting

• Many have slide rules inherited from parents or grandparents (engineers, scientists, toolmakers, military, pilots) that they cherish more as artifacts than tools.
• Large classroom slide rules hanging above blackboards are remembered as symbols of a previous era; some were rescued and now serve as office decor and teaching props.
• Multiple commenters keep small collections, including vintage or pre‑WWI rules, but are reluctant to use fragile specimens.

Educational and cognitive value

• Strong agreement that slide rules are excellent for teaching logarithms, scientific notation, and mental estimation of orders of magnitude.
• Several argue that because you must estimate the result and track exponents yourself, you develop better numerical intuition and are less likely to blindly accept absurd calculator outputs.
• The physical, analog nature—larger numbers to the right, continuous scales—helps prevent certain errors (e.g., confusing 987 with 187) and makes scaling behavior more “visceral.”
• Slide rules and Vernier scales are cited as powerful examples of visual/analog aids to “computational thinking.”

Analog computation, tradition, and backups

• Discussion branches into nomograms, Smith charts, abaci, sextants, torpedo “Is/Was” wheels, and mechanical calculators (Curta) as kindred analog tools.
• Some liken learning these to honoring historical practice in navigation, sailing, or gliding—valued both for robustness without power and for the “purity” and simplicity of the experience.

Limitations and attitudes today

• Many admit they haven’t used one in decades or only use them “for fun,” calling it a “dead skill” and slower/less precise than calculators.
• A minority intentionally use slide rules to slow down, think about numbers, or “keep the muscle memory fresh,” seeing that as worthwhile despite modern alternatives.